The present invention relates to setting an alternating route (detour) in an ATM communication apparatus which realizes the function of multiplexing or switching and more particularly to ATM path changing method and system for realization of changing a transmission path or a virtual path (hereinafter referred to as VP) at a high speed.
In a conventional ATM communication network, for the sake of changing a transmission line or a VP, a method is employed as described in JP-A-2-90834, according to which an information table is retrieved on the basis of information of a cell header, an output (or outgoing) transmission line or path is selected and the function of concentration or cross-connect is realized; and besides the output transmission line or path is changed by causing the central processing unit to rewrite the information table and thereafter retrieve the renewed table. A method for change of transmission line is described in NEC Technical Report (March 1990, pp.9-15), according to which an emergency transmission line is provided and in the event that a failure occurs in a normal route, changing to the transmission line of an emergency route is effected after detection of the failure by means of a switch included in the system.
Further, U.S. Pat. No. 5,093,824 discloses a method in which in the event of the occurrence of a failure, a node detecting this failure prepares a message, the message is transmitted from one node to another to flood the network with the message so as to inform each node of a network topology, whereby the individual nodes are allowed to have in common a correct state which makes the precedently owned network topology coincident with each other so as to reconstruct the connection of the network, thereby avoiding the failure.
JP-A-4-88738, JP-A-4-156139 and JP-A-5-3489 disclose alternating (detouring) operations.